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Topic: Mobile Wood Fired Oven (Read 7349 times)

Hello, I've recently started gathering supplies for building my own wood fired oven, right now I've got firebricks and refractory mortar... everything else I would assume I could buy locally... but I'm not even sure the amount of materials I will even need... Is there some kind of detailed (and straightforward) guide showing how to build your own and how to mount the oven on a trailer correctly (and safely)... I have looked around without much success trying to find something that actually just spells it out clearly and plainly. If anyone could point me in the right direction I would be very grateful.

Seems like people like to buy their ovens pre-built on these forums, but it doesn't make sense to me considering the materials are relatively cheap, (probably about 1000 bucks total for the materials and the trailer) and these companies charge 5000 and up for just the oven and then a thousand to ship it to you... and about 3x times that for the portable variety...

That is a fantastic project! Unfortunately there is no easy instruction to follow that I know of. I am sure there are other threads on this forum that more knowledgeable members may point you to.

People often buy casted ovens because once on the road you want to make sure you oven dome is not going to collapse.Once you oven it nice and hot, the materials expended and you drive it on the road, what is going to do that the bricks are not going to get dislodge and fall?

I would be happy to help you build your mobile oven with what I know.

The first steps would be to have a drawing. Do you have a design, drawing and measurement for you oven already?Did you already pick a trailer to mount it on?

Yes, I have an idea of what trailer I want (was told that NATM certified trailers are what is used by some of these portable oven companies), I just need to know how/where to mount the oven on the trailer so it rides properly. I know these guys are trying to make a living selling this stuff but it seems like a huge markup for what you're getting... (it's just a pile of mud in the end, afterall)... I guess I could make a circle to sort of figure out how much cooking space I'll need and base the dome around that... that's no big deal... but I've read that the dome has to rise in a certain height in order for there to be proper air circulation inside the oven... It's just these tiny details that could make or break the oven that I worry about...

I know these guys are trying to make a living selling this stuff but it seems like a huge markup for what you're getting... (it's just a pile of mud in the end, afterall)...

Well I am one of these guys

That said I am on the forum to help.

For the placement, you want to do 40% of the weight distributed toward the back of the trailer and 60% towards the front. At the end the tongue weight should be right around 10% of your trailer. And that is not easy to do as I just built one.

For the height of the dome, you just opened a big can of worm Many people believe in a 63% door to dome ratio. I personally tend to disagree and have a few people testing it out for me. But you have the right idea, make a circle, build a sphere shaped pile of sand and place your bricks around it.

Can't wait for other members to chime in, that is going to be a fun one.

Excellent, well if you don't mind me trying to attempt this myself I will definitely appreciate any guidance you can provide...

And as I was saying in the other thread, I need that trailer type that you said you custom order... but I don't want to pay high shipping costs... small trailers like that are around 800 or less locally, and I could just get one similar for probably even less than that... what are the absolute necessary specifications these trailers must have?

It appears that everyone puts the ovens on a flat metal sheet that has a lip... what are the specifications of that part and how does it attach to the trailer?From what I've seen, they pour normal concrete in it, and then put the bricks on top of that and start building the dome on top of all this... is that correct?

And is it necessary to make a layer of insulating concrete around the refractory mortar and firebricks? That's also a step I was skeptical about...

I apologize for all the questions, this has been something I've been wanting to do for so long and it's a dream of mine to have my own portable pizza business... however, lack of money and knowledge has held me back for awhile... I appreciate all the help I can get.

I would assume the dome could collapse...? Trailer would still be in one piece, however, and I'd be out for maybe a hundred dollars in refractory mud and concrete and probably a few weeks of time as well... not the end of the world Have you guys heard of people's domes collapsing, another guy that makes pre-built ones claimed to never have any of his collapse...

You won't find a quality trailer for $800. Yes, Lowe's may have one for $800 but the cargo weight it too limited.You want a trailer with a 3k lbs axle minimum. The one on the picture is 3,5K lbsYou are already talking about pouring concrete, you may want to calculate your wait on your total project before buying the trailer.

Also unless you raise the bed of the trailer, you will brake your back using the oven. I recommend a 40" minimum oven floor height with jacks to raise you oven.

To attach the metal sheet to the trailer, you want to weld it. It is the safest.

My advice, don't be cheap on the insulation or you will be sorry later. You really want to use ceramic fiber for the insulation as it is light weight and very efficient. For a trailer like that you want a minimum of 2" at the bottom and 3" on the top. More would be better.

What is the intended use of the oven? Is it for home or commercial purpose?

I would assume the dome could collapse...? Trailer would still be in one piece, however, and I'd be out for maybe a hundred dollars in refractory mud and concrete and probably a few weeks of time as well... not the end of the world Have you guys heard of people's domes collapsing, another guy that makes pre-built ones claimed to never have any of his collapse...

What if that dome collapsed going down the highway? I've seen pictures where that happened and more-you should be able to search them. I've also seen people that have built ovens that seem to function fine. Whether it was simple or not I'm not sure.

My point was I think you need to think of it more than just slapping a "pile of mud" onto a trailer.

I probably won't be going on major highways anytime soon with it, but if it collapses I would just deal with it. *shrug*You run the risk regardless of who builds it, eh?I would rather spend a few hundred dollars repairing it than having forked out 20k from the get-go... (which is a price I have been quoted for a low-end portable oven shipped)

You may not see wood fired ovens as just a pile of mud, but to me the only complicated bit is making it portable... otherwise I could have already built this thing for home use purposes.In the end, that's all they really are... I mean it's a pretty primitive form of cooking, eh? Why should something like that have to be expensive?I guess a lot of people that build these things are on these forums and some of these points of view may not be popular with them... but I think for people with small budgets (like me), these facts are important to talk about...

You are correct, a wood fired oven at it's simplest is a cavity surrounded by dense thermal mass surrounded by insulation. Making one that will be worth a damn for commercial purposes is going to take a lot more then that, and a LOT more then $100 in refractory. Using the cheapest refractory I can source locally to build a small low mass oven you would spend at least 3 times that. A oven big enough to do commercial quantities with enough mass to maintain heat for long events would at least double that number. Still cheaper then buying, but no where near $100.

Can't you just use red clay brick/firebrick for the dome and just use refractory mortar to keep it altogether? I can buy 50lbs of refractory mortar for 65 bucks... How much do you estimate one would need using this method?

These are very strange responses... would think people would strive to build their own for as cheap as possible...? Shuboyje, all the portable wood fired ovens I've seen are made of brick and mortar... which ones are you referring to?

I'm looking at 99.9% of mobile ovens in this world including every single one owned by a member of this site that I know of. Where are you seeing brick and mortar mobile ovens? Are you clear on the difference between a brick and mortar oven and a modular oven?

Brick and Mortar being not Cast in a mold or solid type one concrete pieces Brick being brick which is not meant for the rigors of the road the FGM is Modular oven with a brick finish. PicolonForno classico is a ? John

Okay, so when it's got a mold around the bricks and mortar, it becomes a "modular oven"... (which is still made of bricks and mortar) Can you understand my confusion? You guys shouldn't assume that people know all the phrases and such that you all know, eh? I planned on putting an insulating layer around the bricks... is there some kind of difference?

I think you need to put some type of refractory concrete around your bricks to make sure everything is binding together.

For the insulation you can do a mix of perlite/vermiculite mixed with Portland cement. But for a trailer build it is going to quickly add some weight.The best are layers of ceramic fiber blanket, no less than 3" thickness.

I personally would not consider the a brick and mortar oven then covered in refractory a modular oven. Like I said, brick and mortar portables exist, but are the minority. For instance I've never seen anyone using a fornoclassico mobile oven, and the only one I can find appears to be owned by them. Even then I'm sure it is their modular oven which is exactly as you described, a brick oven encased in cast refractory. Personally I do not think that is the right method for a beginner builder, a mobile oven, or someone look for a cheap oven. The refractory would need to be a couple inches thick minimum to be strong enough, so the cost would be high, the weight would be high, and the mass would be high, so it would take longer to heat. The only way to avoid that would be to build a very thin brick dome so that even with the cast outer section the oven would not be too massive, but an oven built from extra thin bricks is not something I would recommend for a first oven.

At that point you are back to using castable anyway, so might as well just cast an oven to begin with. We'll walk you through it and help you get it done right, I promise you we have a good group here who just want to help.

Casting is pretty simple, think concrete, just instead of Portland Cement you use Calcium Aluminum Cement, which is much better for high temperature. Normally your Calcium Aluminum Cement would come in the form of a commercial castable refractory. A commercial castable refractory will have the calcium aluminate cement, proper aggregates and special ingredients to allow moisture and steam to escape. The cheapest one I can get locally(perfectly good to use for an oven) has a yield of 124lbs per cubic foot. It costs $27 for a 55lb bag. To figure cost you would need to come up with an oven design, find how many cubic feet it is, and then do the math, but that is way ahead of where we are now. I can tell you a small low mass oven that would not be suitable for commercial use would be about 3 cubic feet. My math says that would take 7 bags at a cost of $189 for me locally. I personally would also add stainless needles. They act like rebar in concrete, and work well at 2% by weight. I'm in a big city and still couldn't source them locally, but they are easy to buy on ebay. The example oven I mentioned would need about 10lbs. With shipping that's $35. So now we are at $225 for a small low mass non commercial oven, as I mentioned before for a commercial size oven I would guess you will double that. I'm guessing that doesn't fit your budget from what you've said. You could make your own castable refractory mix, but you would be forging your own path. Locally I can get an 80lb. bag of Calcium Aluminate cement for $60. If you have a source for old brick, you could use crushed brick and sand as an aggregate. I'd bet you could cast a commercial oven for $150 if you have a source for free old brick. It would lack the special ingredients to vent moisture and steam which would probably lead to more cracking, but the cracks would be aesthetic, all cast refractory will crack regardless.

Take this all in and if any of it sounds like it could work for you we can help you figure out the next step.